I try to avoid foreshadowing, and stay in the moment. However, I will have the MC, or another character, contemplate a set of possibilities that may occur and sometimes they consider their options, but I try to not focus on the possibility that will be followed, assuming of course I mention what will eventually happen.
That's typically how I foreshadow. The characters will discuss different possible options, one will foreshadow what happens, possibly highlighting how it's likely to go wrong, while the others are red-herrings, so the readers won't guess which outcome is more likely.
I also so asides—often set-aside with em-dashes so the readers pay more attention to it—which highlight what's likely to happen. For example:
Someone should try that technique—though there's no telling what the response might be—as it may give us a substantial leg up.
That way, you never explicitly tell them what's going to happen, but you're emphasizing it so they'll remember it when it does happen.
My feelings about abandoned story threads is that when the reader encounters one, they try to integrate it into the main thread as they perceive it at that point. That leads to speculation as to where the story will go and that can enhance the reading experience. When I read a story that does not have these 'red-herrings' I find that the author is often predictable and the finale is not a surprise.
If you plan your red-herrings, then you don't need to rely on accidental red-herrings.
I typically put a lot of thought into my red-herrings (which might be why some don't feel there are enough of them). But then, I also place them where they're more essential (amidst the foreshadowed elements, so the readers don't know where the story is going in the first place).